The ability to maintain the integrity of nucleic acids in a biological sample (and in particular, those contained in diagnostic samples obtained from human patients), whether the specimen is taken in a remote field location, a doctor's office or in a laboratory, often determines whether the nucleic acids can be successfully analyzed. Typically, nucleic acids in a biological sample will quickly degrade and/or denature at ambient temperatures. This problem is magnified when a specimen is collected at a remote field site, or a significant distance from a doctor's office or laboratory environment, and especially where there may be limited or no access to refrigerator/freezer conditions. Problems associated with the collection and handling of biological specimens are further exacerbated when the desired nucleic acids for downstream analysis include ribonucleic acid (RNA), which is particularly susceptible to degradation by endogenous or exogenous nuclease activity.
Another concern when working with biological specimens is the risk of release of infectious agents to individuals and the environment and, in addition, contamination to the biological specimen itself. This is especially true with regard to the handling of potentially infectious biological agents such as Ebola, avian influenza, severe acute respiratory syndrome (SARS), and many others.
Molecular diagnostics has changed drastically with the advent of polymerase chain reaction (PCR) and thereafter with real-time PCR. Nucleic-acid based detection platforms employing e.g., quantitative real-time PCR (qPCR) or reverse transcriptase PCR (RT-PCR) and quantitative, real-time, reverse transcriptase PCR (qRT-PCR) assays can deliver results in hours versus days required for traditional culture and isolation methods making molecular detection methods the mainstay of modern diagnostic laboratory analysis.
Several commercial companies (e.g., Qiagen [Valencia, Calif., USA], Roche Applied Science [Indianapolis, Ind., USA], Gen-Probe [San Diego, Calif., USA], and bioMérieux [Durham, N.C., USA]) have developed instruments to automate the nucleic acid extraction process from sample isolation to molecular analysis. For example, the Tigris DTS® (Gen-Probe, San Diego, Calif., USA) automates the entire detection process, and in late 2004 was approved by the U.S. Food and Drug Administration (FDA) for simultaneously detecting Chlamydia trachomatis and Neisseria gonorrhoeae using Gen-Probe's APTIMA COMBO-2® amplified nucleic acid test (NAT) assay.
In view of the requirement for high-quality nucleic acid samples in contemporary detection and assay systems, there is a need in the art for safe and facile collection and analysis of high-quality quality nucleic acids contained within a variety of biological samples and specimens. There is also a need for high efficiency in the collection of nucleic acids. For nucleic acid testing, the issue is not always the absolute amount of the sample collected, but the amount of nucleic acid recovered from the sample. Inefficient recovery of nucleic acids requires repeated collection efforts, which are not always possible. There is also a need for more rapid collection efforts that can be automated for efficient high-throughput methods to recover the highest percentage of nucleic acids possible from the biological sample collected, so that samples can be appropriately and rapidly analyzed for a variety of nucleic acids including RNA and DNA, genes, genomes and specific sequences.